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Legend
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Discussion Starter · #1 ·
I did a search a while ago, and a company called Gefen apparently has a HDMI to coax "extender" (their words) which was supposed to be on the market earlier this year.

Just wondering if anyone has installed/used any brand of an HDMI to coax converter and any success stories?

thanks in advance

Mods, feel free to move this thread to another forum topic if needed.
 

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Legend
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Discussion Starter · #4 ·
Doug Brott said:
philmalik,

How far are you trying to extend?
We need to go from the downstairs rec room to the upstairs TV. I'm guessing 100 to 150 feet. (or more).

It's already prewired for coax, and right now I'm sending the signal from my Hr20-700 to my VCR via RCA jacks, then out from the VCR via coax up through the house, up to another VCR, and out the VCR via RCA jacks to the TV upstairs.

I have no plans on buying another receiver as I only watch either the TV upstairs or downstairs TV but not both at the same time.

And with the IR remote from the HR20-700 I can operate it from wherever in the house.

I would just like to get an HD feed up to my HD TV in the kitchen.

thanks
 

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I have used the OWLink HDMI over fibre optic, works great! :)

Cheers,
Tom
 

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philmalik said:
I did a search a while ago, and a company called Gefen apparently has a HDMI to coax "extender" (their words) which was supposed to be on the market earlier this year.

Just wondering if anyone has installed/used any brand of an HDMI to coax converter and any success stories?

thanks in advance

Mods, feel free to move this thread to another forum topic if needed.
Probably not, because it wouldn't work over 1 coax cable. Can you use the existing coax to fish cat5 through the wall?
 

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Grentz said:
You can use the shield as a lead though, that is what many of the rca -> coax baluns do.
i can positively say i've never seen a device that does that. who makes such a thing? RCA type cable is coaxial cable, so I'm not sure of the purpose of the balun. You're going to have to show me how that possibly works (using shield to transmit sound/video). UTP cable is what you use for RCA baluns, or just run coax and compress an RCA connector on the end of it.

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One thing I want to make sure you guys are clear on that geffen product before you buy it, RGBHV cables do not transmit sound. Only R, G, B, horiz & vert sync.
 

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The Shadow Knows!
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I remember being told that there was a standard for high-bandwidth over RG6 cable that was being used for broadcast centers but it was rejected because it contained no copy protection. If you think about it, given the amount of data that travels from the satellite to the TV there's clearly enough bandwidth over a single RG6 run to support a single 19.2 megabit stream. The problem is more legal than technical... making sure that the HDMI handshaking was taking place in a way that satisfied the sending unit.
 

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Broadcast Engineer
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brant said:
RCA type cable is coaxial cable, so I'm not sure of the purpose of the balun...
It is indeed coaxial, but it is not equivalent to coax such as that designed to transport RF. RG-6, for instance, has a characteristic impedance of 75 ohms, which means that to an RF signal it appears as an infinite piece of waveguide tuned to and capable of carrying high frequencies at low loss. Baseband signals, on the other hand, such as analog audio and video which exist at much lower frequencies do not need to use the same technology, and can be transported through coax that basically just makes a physical connection (and does not need to work at higher frequencies) not much different than the same way DC or AC power is transported.

"Balun" is short for "balanced-unbalanced" and typically refers to an impedance-matching transformer, such as the kind that can convert 300-ohm twinlead to 75-ohm coax, or to an audio transformer that can convert low-Z balanced signals to high-Z unbalanced (or vice versa). If you were converting an unbalanced signal to balanced to provide interference-rejection capability, a balun would be in order. That is probably a similar reason to why a balun might be needed in the instance you refer to.
 

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brant said:
i can positively say i've never seen a device that does that. who makes such a thing? RCA type cable is coaxial cable, so I'm not sure of the purpose of the balun. You're going to have to show me how that possibly works (using shield to transmit sound/video). UTP cable is what you use for RCA baluns, or just run coax and compress an RCA connector on the end of it.

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One thing I want to make sure you guys are clear on that geffen product before you buy it, RGBHV cables do not transmit sound. Only R, G, B, horiz & vert sync.
I have some old low voltage IR/Video sender stuff that uses the coax as two leads.

You can also try it yourself, I hacked together some adapters that allow you to run two leads through a coax cable. The center pin is one, and the outer screw (or shield) is the other.

Not say it is ideal, but it works.
 

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TomCat said:
It is indeed coaxial, but it is not equivalent to coax such as that designed to transport RF.
my point is that you can run composite through the existing coax, if you had enough lines. it was my interpretation that the poster was saying the HDMI-RGBHV converter would use the shield as a conductor to transmit the signal; that is not true. that converter would be used to change an a projector w/ RGBHV inputs to one w/ HDMI inputs; no sound.

using the shield as a conductor sounds like a terrible idea.
 
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